1. Field of the Invention
The present invention relates to sliding shaft surgical instruments. More specifically, the present invention relates to a sliding shaft surgical instrument with an improved guidance means for guiding the sliding shaft and detaching the sliding portion for ease of cleaning.
2. Description of the Related Art
The related art involves surgical instruments of this generic type which are also known as sliding shaft instruments which have a shaft with a stationary handle part. A sliding part, which is axially displaceable by means of a pivotable handle part, is guided on the shaft. Working elements, which can be operated by the axial displacement of the sliding part, are arranged on the distal end of the shaft and of the sliding part. If the instrument is designed as a punch, for example, then cutting edges are formed on the distal end of the shaft and of the sliding part, these cutting edges being moved by the axial movement of the sliding part to sever tissue, cartilage, bone or the like.
Distal and proximal guidance means, which guide the sliding part in a sliding plane on the shaft within an axial working stroke for actuation of the working element, are provided for guiding the sliding part on the shaft. In this process, the axial displacement of the sliding part is limited at the proximal end of the working stroke by locking means, so that the distal and proximal guidance means remain engaged while the instrument is in use and keep the sliding part guided on the shaft. The locking means may be unlocked, so that the sliding part is movable into a cleaning position in the proximal direction beyond the limited working stroke. In this cleaning position, the guidance means are disengaged, so the sliding part can be lifted away from the shaft to be able to thoroughly clean and sterilize the instrument.
There are known instruments with which the sliding part is completely separated from the remaining instrument in the cleaning position (e.g., DE 201 03 630 U1). With other instruments, however, the sliding part is connected to the remaining instrument, but cannot be pivoted away from the shaft. However, in the case of an instrument known from EP 1 092 397 B1, which issued Dec. 7, 2005, to Tontarra for a Surgical Instrument, the sliding part is connected to the pivotable handle part on its proximal end. In the case of an instrument known from U.S. Pat. No. 5,961,531, which issued Oct. 5, 1999, to Weber et al. for a Convertible Rongeur, the sliding part is connected by an pivot pin to the stationary instrument part by means of a connecting piece. Locking means are known in a wide variety of embodiments, e.g., from U.S. Pat. No. 6,126,674, US 2003/0088268 A1 and EP 1 092 397 B1.
With the known instruments, the distal guidance means and the proximal guidance means each have a guidance web having a T-shaped cross-sectional profile running axially, engaging with a corresponding T-shaped cross-sectional profile in the area of the working stroke in a guidance groove. In the cleaning position, the guidance webs emerge from the guidance grooves in the proximal direction, so that they can be lifted out of these guidance grooves to lift the sliding part away from the shaft. The guidance webs and the undercut guidance grooves are complex to manufacture. The undercut T-shaped guidance grooves also make cleaning of the instrument difficult.
What is not appreciated by the prior art is the need for simpler, more cost effective manufacturing of sliding shaft surgical instruments. Additionally, there is a need for a sliding shaft surgical instrument that is more easily cleaned and serviced.
Accordingly, there is a need for an improved surgical instrument which will permit simpler fabrication and cleaning.